The invention relates generally to an electromagnetically actuated clutch and more particularly to a clutch having a multiple pole electromagnetic actuator.
The majority of four-wheel drive motor vehicles and virtually every sport utility vehicle or pick-up truck equipped with four-wheel drive utilizes a transfer case driven by the output of the transmission to distribute drive torque to the front and rear drive lines of the vehicle. These transfer cases incorporate many diverse mechanical devices which may provide, among other features, a reduced speed (low gear) drive mode, interaxle speed differentiation and manual or automatic engagement of an interaxle clutch to intermittently reduce prop shaft speed differences or positively drive front and rear prop shafts.
Significant developments have been made with regard to systems which sense wheel speed differences and engage interaxle clutches to reduce such speed differences. An automatically engaging system is disclosed, for example, in co-owned U.S. Pat. No. 5,407,024.
In addition to developments directed to enhancing the flexibility and operation of such transfer cases are developments directed to providing smooth, seamless operation of the components of the transfer case such as the interaxle clutch as well as increasing torque capacity of such a clutch. The present invention is directed to such a feature.